From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Petr Mladek <pmladek@suse.com>, Steven Rostedt <rostedt@goodmis.org>
Cc: Jan Kara <jack@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Eric Biederman <ebiederm@xmission.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.com>, Pavel Machek <pavel@ucw.cz>,
Andreas Mohr <andi@lisas.de>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
linux-kernel@vger.kernel.org,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: [RFC][PATCHv3 1/5] printk: move printk_pending out of per-cpu
Date: Tue, 9 May 2017 17:28:55 +0900 [thread overview]
Message-ID: <20170509082859.854-2-sergey.senozhatsky@gmail.com> (raw)
In-Reply-To: <20170509082859.854-1-sergey.senozhatsky@gmail.com>
Do not keep `printk_pending' in per-CPU area. We set the following bits
of printk_pending:
a) PRINTK_PENDING_WAKEUP
when we need to wakeup klogd
b) PRINTK_PENDING_OUTPUT
when there is a pending output from deferred printk and we need
to call console_unlock().
So none of the bits control/represent a state of a particular CPU and,
basically, they should be global instead.
Besides we will use `printk_pending' to control printk kthread, so this
patch is also a preparation work.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Suggested-by: Petr Mladek <pmladek@suse.com>
---
kernel/printk/printk.c | 26 ++++++++++++--------------
1 file changed, 12 insertions(+), 14 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index a1aecf44ab07..2cb7f4753b76 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -401,6 +401,14 @@ DEFINE_RAW_SPINLOCK(logbuf_lock);
printk_safe_exit_irqrestore(flags); \
} while (0)
+/*
+ * Delayed printk version, for scheduler-internal messages:
+ */
+#define PRINTK_PENDING_WAKEUP 0x01
+#define PRINTK_PENDING_OUTPUT 0x02
+
+static unsigned long printk_pending;
+
#ifdef CONFIG_PRINTK
DECLARE_WAIT_QUEUE_HEAD(log_wait);
/* the next printk record to read by syslog(READ) or /proc/kmsg */
@@ -2709,25 +2717,15 @@ static int __init printk_late_init(void)
late_initcall(printk_late_init);
#if defined CONFIG_PRINTK
-/*
- * Delayed printk version, for scheduler-internal messages:
- */
-#define PRINTK_PENDING_WAKEUP 0x01
-#define PRINTK_PENDING_OUTPUT 0x02
-
-static DEFINE_PER_CPU(int, printk_pending);
-
static void wake_up_klogd_work_func(struct irq_work *irq_work)
{
- int pending = __this_cpu_xchg(printk_pending, 0);
-
- if (pending & PRINTK_PENDING_OUTPUT) {
+ if (test_and_clear_bit(PRINTK_PENDING_OUTPUT, &printk_pending)) {
/* If trylock fails, someone else is doing the printing */
if (console_trylock())
console_unlock();
}
- if (pending & PRINTK_PENDING_WAKEUP)
+ if (test_and_clear_bit(PRINTK_PENDING_WAKEUP, &printk_pending))
wake_up_interruptible(&log_wait);
}
@@ -2740,7 +2738,7 @@ void wake_up_klogd(void)
{
preempt_disable();
if (waitqueue_active(&log_wait)) {
- this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
+ set_bit(PRINTK_PENDING_WAKEUP, &printk_pending);
irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
}
preempt_enable();
@@ -2756,7 +2754,7 @@ int printk_deferred(const char *fmt, ...)
r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args);
va_end(args);
- __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
+ set_bit(PRINTK_PENDING_OUTPUT, &printk_pending);
irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
preempt_enable();
--
2.12.2
next prev parent reply other threads:[~2017-05-09 8:30 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-09 8:28 [RFC][PATCHv3 0/5] printk: introduce printing kernel thread Sergey Senozhatsky
2017-05-09 8:28 ` Sergey Senozhatsky [this message]
2017-05-25 12:11 ` [RFC][PATCHv3 1/5] printk: move printk_pending out of per-cpu Petr Mladek
2017-05-25 12:36 ` Sergey Senozhatsky
2017-05-25 12:43 ` Petr Mladek
2017-05-09 8:28 ` [RFC][PATCHv3 2/5] printk: introduce printing kernel thread Sergey Senozhatsky
2017-05-10 5:59 ` Sergey Senozhatsky
2017-05-29 9:29 ` Petr Mladek
2017-05-29 12:12 ` Jan Kara
2017-05-31 7:30 ` Sergey Senozhatsky
2017-05-31 21:44 ` Andreas Mohr
2017-06-01 7:21 ` Sergey Senozhatsky
2017-06-01 7:23 ` Sergey Senozhatsky
2017-06-01 9:20 ` Sergey Senozhatsky
2017-06-28 13:17 ` Petr Mladek
2017-06-29 7:40 ` Sergey Senozhatsky
2017-06-28 12:45 ` Petr Mladek
2017-05-31 7:22 ` Sergey Senozhatsky
2017-06-28 12:19 ` Petr Mladek
2017-06-29 6:26 ` Andreas Mohr
2017-06-29 7:00 ` Andreas Mohr
2017-06-29 7:33 ` Sergey Senozhatsky
2017-06-29 11:24 ` Tetsuo Handa
2017-06-30 7:01 ` Sergey Senozhatsky
2017-06-30 10:18 ` Tetsuo Handa
2017-06-30 11:57 ` Sergey Senozhatsky
2017-06-30 12:35 ` Tetsuo Handa
2017-06-30 12:50 ` Sergey Senozhatsky
2017-06-30 13:16 ` Petr Mladek
2017-06-30 13:38 ` Sergey Senozhatsky
2017-07-03 11:11 ` Sergey Senozhatsky
2017-07-02 20:27 ` Pavel Machek
2017-07-05 16:36 ` Sergey Senozhatsky
2017-07-03 19:34 ` Steven Rostedt
2017-07-04 5:26 ` Sergey Senozhatsky
2017-07-04 6:53 ` Sergey Senozhatsky
2017-06-30 14:10 ` Sergey Senozhatsky
2017-06-30 11:54 ` Petr Mladek
2017-06-30 12:42 ` Sergey Senozhatsky
2017-06-30 13:33 ` Steven Rostedt
2017-06-30 14:28 ` Sergey Senozhatsky
2017-06-30 14:45 ` Steven Rostedt
2017-07-01 1:50 ` Sergey Senozhatsky
2017-07-04 14:03 ` Petr Mladek
2017-07-05 5:02 ` Sergey Senozhatsky
2017-05-09 8:28 ` [RFC][PATCHv3 3/5] printk: add enforce_emergency parameter Sergey Senozhatsky
2017-05-09 8:28 ` [RFC][PATCHv3 4/5] printk: enable printk offloading Sergey Senozhatsky
2017-05-09 8:28 ` [RFC][PATCHv3 5/5] printk: register PM notifier Sergey Senozhatsky
2017-05-30 9:55 ` Petr Mladek
2017-05-31 6:42 ` Sergey Senozhatsky
2017-06-27 14:45 ` Petr Mladek
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